1. Field of the Invention
The present invention relates to an exhaust gas sensor wherein use is made of the variation of resistance of a metallic oxide semiconductor and to a process for producing the same, and more particularly to improvements in exhaust sensor materials.
Exhaust gas sensors are used for detecting the air/fuel ratio .lambda. of exhaust gases or O.sub.2, CO or like component of exhaust gases. They are chiefly used for controlling the air/fuel ratio for motor vehicle engines, boilers, etc. and for preventing incomplete combustion in air heaters. For use with motor vehicle engines and boilers, the sensor controls the air/fuel ratio: at the point of equivalence (where the air/fuel ratio .lambda. is 1.00) or in the lean burn region (in which the air/fuel ratio is not smaller than 1). For use in air heaters, the sensor detects the reduction of the air/fuel ratio .lambda. to below 1 and detects incomplete combustion.